1. Field of the Invention
This invention relates to an improvement in the maintenance characteristic (decrease in light output with operating time) of a gas discharge lamp.
2. General Background
Such a gas discharge lamp has been in the shape of a 100 watt incandescent lamp and is referred to as a beam mode discharge (BMD) lamp. A shortcoming of this lamp is the reduction of emitted light during operation due to the deposition of cathode material on the phosphor surface.
The general operating principles of the BMD lamp and related prior art have been described previously. The particular BMD lamp embodiment modified by this disclosure is described in U.S. Pat. No. 4,408,141, "Dual Cathode Beam Mode Fluorescent Lamp". Additional BMD patents which have been issued are: U.S. Pat. No. 4,413,204, "Non-Uniform Resistance Beam Mode Fluorescent Lamp"; U.S. Pat. No. 4,450,380, "Multielectrode Array For A Beam Mode Lamp"; U.S. Pat. No. 4,494,046, "Single Cathode Beam Mode Fluorescent Lamp for DC Use"; U.S. Pat. No. 4,521,718, "Beam Mode Lamp with Voltage Modifying Electrode"; U.S. Pat. No. 4,516,057, "Multielectrode Array For A Beam Mode Fluorescent Lamp"; and U.S. Pat. No. 4,518,897, "Twin Anode Beam Mode Fluorescent Lamp".